Well drilling guide



Nbv. 5, 1963 PUGH 3,109,501

WELL DRILLING GUIDE Filed Nov. '7, 1960 26 2 l0 5 6 3 %V/////// /7 /Z= 2.0

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INVENTOR. JAMES B. P UGH ATTORNEYS State The invention relates to well drilling equipment and more particularly to gyroscopic stabilizers arranged for use in a rotary drill string for maintaining the rotary drilling bit in substantially the same deviation plane as at the start of the drilling.

In rotary drilling, and especially in high speed rotary or turbine drilling, the drill string spirally drifts from an absolute vertical line along the desired drill course. This drifting occurs from the precession of the rotary action of the drill, and other deviation occurs by actual deflection of the drill head contacting or impinging on a hardened strata and in particular on inclined strata.

According to the present invention there is provided a gyroscopic guide for a rotary drill bit which maintains the bit in substantially the same deviation plane as when the drilling was commenced, and which prevents the drill head from drifting from the desired course. The gyroscopes are operated by the activating fluid for the rotary drill bit. Such fluid may be air, gas, drilling mud or other convenient fluid used under pressure to turn the drill head or the turbine running the drill bit. The device is arranged in odd numbers of gyroscopes running in opposite directions so as to provide an essentially balanced string for a high speed rotary drilling string.

Included among the objects and advantages of the invention is to provide a stabilizer for guiding a drill string essentially without deviation from a desired course.

Another object of the invention is to utilize the fluid under pressure which drives the drill head for rotating gyroscopic stabilizers for the drill string. The device provides a simple and highly effective guide means which does not essentially change the set-up on the drill string and provides highly effective gyroscopic guide members for controlling the lateral movement of the drill string. The invention uses such gyroscope members to oppose the torque of the drill head or turbine and in opposed series to themselves.

These and other objects and advantages of the invention may be readily ascertained by referring to the following description and appended illustrations in which:

FIG. 1 is a longitudinal section of a gyroscope stabilizer according to the invention;

FIG. 2 is a cross-sectional view of the gyroscope and stabilizer of FIG. 1 taken along the section line 2-2;

FIG. 3 illustrates a drill string with one method of using the gyroscopes of the invention included in the drill string and positioned above the drilling head; and

FIG. 4 illustrates one action of the gyroscopically controlled drill string according to the invention in striking sloping underground strata.

In the device illustrated in FIG. 1, a central shaft 1%! is provided with a passage 11 therethrough. A tool joint box 12 is integrally attached to the shaft il and this is arranged for threaded attachment by means of threads 13 to drill pipe, drill head box, another gyro, or the like. At the opposite end, the shaft 16 has a series of fine threads 14- for threaded attachment to a headpiece 15, which includes a drill collar pin 16. The drill pin is arranged for threaded attachment to other par-ts of the drill string which may be drill pipe, another gyro set, or the like. The passage 11 through the shaft 1t communicates with passage 17 in the head 15 which in turn communicates with larger passage 18 in the pin 16. A lock ring 269 and 21 is threadedly engaged to the respective exteriors of the head 16 and the tool atent A joint box 12. Each lock ring is secured in position to its supporting set screws 22, which may in the preferred form be a series of set screws spaced around the ring for securely locking the ring in position on the headpiece. The number of set screws required is dependent on the size of the ring. The lock ring 21 is, likewise, secured to the tool joint box by means of set screws 23.

A gyro cylindrical casing 25 provided with a plurality of internal turbine blades 26 is mounted around the shaft 10 between the rings 20 and 21. A hearing set 27 mounted on the headpiece 16 and a bearing set 28 mounted on the tool joint box 12 support the casing 25 and provide for free rotation of the gyro casing around the shaft 10. The rings must be spaced from the ends of the casing for free rotation and are close enough to prevent entrance of drill chips. Seals 30 at each end of the casing seal the ends of the turbine to the lock rings. With this configuration it is seen that the casing 25 freely rotates around the shaft 11 with the seals preventing leakage of fluid and entrance of foreign matter.

Fluid such as drilling mud, air, etc. normally is conveyed through the drill string. With a gyro in the string, when the fluid reaches the passage 18 it is partially deflected through ports 33 and 34 which convey the fluid under pressure into the turbine compartment for rotating the gyro or turbine casing 25. Ports 35 and 36 at the opposite end of the turbine casing return the fluid into central passage 37 in the joint box 12 and ultimately into the next drill string section. A choke or exit port 38 may be utilized to control the volume of the fluid passing through passages 17 and 11. This controls the amount of fluid bypassed into the turbine compartment to thereby control the rotational speed of the gyro. Depending on the volume of fluid passing through the system, the choke 38 may be larger or smaller or entirely removed as may be desired.

Since the gyro device is inserted in the drill string, th shaft 10 will rotate with the drill string itself. This, of course, is at the same speed as the drill string since it becomes a part of the drill string. The gyro casing 25, however, rotates at a substantially higher speed and the direction of rotation is independent of the rotation of the shaft 10. Where two or more gyro units are mounted in a'drill string, adjacent gyro units normally would be rotated in opposite directions to provide a balanced system for guiding the drill string.

Depending on the size of the drill string and the hole being bored, the gyro casing may be from five through about twelve inches in diameter, the main criterion being that the diameter of the gyro casing is less than the external diameter of the lock rings so that the gyro casing will run free in the well. The rings should also be less than the diameter of the 'hole so that drill fluid, chips, etc. may pass between the rings and the hole. The overall length of the gyro casing may be from three to thirty feet or more depending on the required gyroscopic force necessary for guiding the tool. The turbines or gyros may be arranged to rotate at a rate of speed through a range of from about 1900 through 20,000 rpm. Again, the choice 'ofrate of rotation is determined by the size of the gyro casing, as Well as its weight to provide the gyroscopic force needed. In mounting the gyroscopic devices in the drill string, it is preferable that they be mounted in odd numbers, that is, three, five, seven and the like. This provides a system so that even pairs may be operated in opposite directions for a balanced action. The extra single gyroscope is rotated in a direction opposite to the rotation of the drill head to balance or counteract the gynoscopic action of the rotary dm'll head. Furthermore, the first of a series of gyroscope devices may be placed from four to ten or more feet above the drilling bed, again depending on the particular drill string.

sloped to the centerline 52 of the well.

As illustrated in FIG. 3, a drill pipe 4t has attached to it a gyroscopic device 5 and it in turn is attached to another piece of drill pipe 41. Subsequently another gyro system 5 is attached to it. Below the lower gyro device another drill pipe 42 is attached. A drill head 43 is attached to the drill pipe 42 for drilling. The lock rings of the gyroscope device should be smaller than the maximum drilling diameter of the drill head so that chips, cuttings and the like carried up by the drilling fluid may freely pass the rings without binding and may pass the rotating gyro cylinder. Where the drilling fluid is a liquid the device is essentially self-lubricating since the fluid itself will provide lubrication in the bearings of the gyro device. Where air is the drilling fluid enclosed bearings may be provided so as to provide adequate lubrication for the high speed rotation of-the gyro.

As illustrated in FIG. 4, a well 5% passing through various strata of the earth is shown with a drilling bit in position to strike a harder strata 51 which is sharply Under normal circumstances when this situation is met, the drill, due to the weight imposed on it, tends to turn into the slope of the harder material deflecting the hole away from the desired center line. As shown in the dashed lines, the normal tendency for the drill bit in striking such a dip is to turn up slope instead of deflecting down along the dip. By utilizing applicants general stabilizers, on reaching such a dip as indicated in FIG. 4 the drill is prevented from deflecting and it is maintained in substantially vertical position and follows the center line 52. Thus in drilling the gyroscopic force of the gyro system prevents lateral movement of the drill.

As pointed out above, the size and weight and rate of rotation of the gyro stabilizers according to the invention must be predetermined for the particular drilling rig. These factors are determined by the force necessary to prevent lateral movement of the particular drill string. This force prevents deflection from strikingvarious strata or other objects or from the normal centrifugal action of the rotary drill, which is a gyroscopic action of the drill head itself under its rotation. This centrifugal action of the drill head causes the hole to spiral downwardly. It is, therefore, seen that the gyro devices easily fit in the drill string without utilizing additional power. They provide the necessary guiding forces for the drill string. By utilizing the fluid for the drill head or the drilling mud itself, no external force is necessary to operate the gyro for producing the guiding forces.

While the invention has been illustrated by reference to a specific device, there is no intent to limit the spirit or scope of the invention to the precise details so set forth, except insofar as defined in the following claims;

I claim;

l. A gyro guide for a drill string comprising: a shaft portion arranged for threaded engagement in a drill string and cooperatively forming a length of the drill string, there being a bore extending through said shaft portion arranged to pass fluid therethrough, a lock ring threadedly engaged on said shaft portion adjacent each end thereof and secured in position against disengagement, a rotatable casing spacedly mounted around said shaft between said lock rings, bearing means mounted on the shaft portion arranged to provide supportfor free rotation of said casing, a plurality of turbine blades interconnected with the casing and arranged to rotate said casing under influence of fluid passing said blades independent of drill string rotation, there being a bypass from the bore through said shaft at each end thereof for passing a portion of the fluid from one end of the shaft into the turbine blades for rotating said casing, and return the fluid into said bore, and seal means between 7 said bearings and said lock rings to prevent, escape of fluid therefrom.

2. A guide according to claim 1 in which said casing 3. A guide according to claim '1 in which the lock I rings have a diameter less than the drilling diameter of the drill string bit.

4. A gyro guide for a drill string comprising: a shaft portion arranged for threaded engagement in a drill string and cooperatively form therewith a length of the drill string, there being a bore extending through said shaft portion arranged to pass fluid therethrough, a radially extending lock ring threaded ly engaged on said shaft adjacent each end thereof and releasably secured in position against disengagement, a tubular casingspaced from and enclosing said shaft between said lock rings, bearing means mounted on the shaft between said rings and arranged to provide free rotative support for said casing, a plurality of turbine blades interconnected with the casing and arranged to rotate said casing under influence of fluid passing said blades independent of drill string rotation, there being a plurality of bypass passages from the bore at each end of said shaft for passing a portion of the fluid flowing through said passage into the turbine blades for rotating force and return the same to the drill string bore, and seal means between said bearings and said lock rings to prevent escape of fluid therefrom.

5. Mechanism for guiding a drill string in a drilling operation including a guide for a drill string com rising a series of at least three gyro guide mechanisms incorporated in the drill string'adjacent the drill head and spaced therefrom for guiding the drill string along a substantially predetermined course, the series of gyro mechanisms being in sets of an odd number and each group of two of the gyro mechanisms being rotated in opposition to another group of two mechanism and the remaining gyro mechanism being rotated in opposition to the drill head to counteract the centrifugal action of the drill head, each gyro mechanism including a central shaft arranged to be threaded-1y engaged in and cooperatively form a portion of the drill string and provide a passage for fluid therethrough cooperative with the passage through the drill string, a lock ning releasably mounted adjacent each end of the shaft and arranged to be held in position during operation, a gyroscope casing encircling said shaft between said rings and arranged for free rotation thereon, there being bearing means adjacent each end of said shaft for providing said free rotation of said casing, at least .one passage extending fromthe central passage in the shaft into the space between the casing and the shaft, a plurality of turbine blades mounted on and internally of the casing for rotating said casing under influence of fluid passing through said passa e into the space, at least one outlet passage from said space into the passage in said shaft downstream from said inlet passage, a seal mounted between the bearings and said lock rings to prevent loss of fluid during operation, and choke means arranged in the passage through said shaft for controlling the volume of fluid passing into the space between said casing and said shaft.

6. Mechanism according to claim 5 in which the remaining gyro mechanism is mounted in the drill string nearest to the drill head.

7. The method of guiding a drill string substantially along a desired course line comprising: inserting in the through the drill string is utilized to rotate said gyroscopic guide members.

9; The method of guiding a drill string substantially along a desired center line comprising: inserting in the drill string at spaced intervals adjacent the drill head of the drill string a series of an odd number of gyroscopie guide members which includes a rotative casing member encircling a portion of the drill string, rotating each pair of said casings in an opposed direction to another pair of said casings, rotating the remaining one of the series nearest the drill head in the direction opposed to the drill head, the rotation of each gyro mechanism being by passing a portion of fluid medium pumped through the drill string through said casings.

References Qited in the file of this patent UNITED STATES PATENTS 

1. A GYRO GUIDE FOR A DRILL STRING COMPRISING: A SHAFT PORTION ARRANGED FOR THREADED ENGAGEMENT IN A DRILL STRING AND COOPERATIVELY FORMING A LENGTH OF THE DRILL STRING, THERE BEING A BORE EXTENDING THROUGH SAID SHAFT PORTION ARRANGED TO PASS FLUID THERETHROUGH, A LOCK RING THREADEDLY ENGAGED ON SAID SHAFT PORTION ADJACENT EACH END THEREOF AND SECURED IN POSITION AGAINST DISENGAGEMENT, A ROTATABLE CASING SPACEDLY MOUNTED AROUND SAID SHAFT BETWEEN SAID LOCK RINGS, BEARING MEANS MOUNTED ON THE SHAFT PORTION ARRANGED TO PROVIDE SUPPORT FOR FREE ROTATION OF SAID CASING, A PLURALITY OF TURBINE BLADES INTERCONNECTED WITH THE CASING AND ARRANGED TO ROTATE SAID CASING UNDER INFLUENCE OF FLUID PASSING SAID BLADES INDEPENDENT OF DRILL STRING ROTATION, THERE BEING A BYPASS FROM THE BORE THROUGH SAID SHAFT AT EACH END THEREOF FOR PASSING A PORTION OF THE FLUID FROM ONE END OF THE SHAFT INTO THE TURBINE BLADES FOR ROTATING SAID CASING, AND RETURN THE FLUID INTO SAID BORE, AND SEAL MEANS BETWEEN SAID BEARINGS AND SAID LOCK RINGS TO PREVENT ESCAPE OF FLUID THEREFROM. 